It's an old riverfront warehouse that was gutted and turned into something else. Upper left is the Quai d'Austerlitz street side of the building. Upper right is the warehouse next door that has not been renovated. (Unaware of any plans for that anyway.) And this is what is now inside the green building. ------>
That is not a party boat. That is public transportation. It is the Voguéo which shuttles from Austerlitz to the veterinary school of Maisons-Alfort in the suburbs. It uses the normal Navigo Paris transport pass or a ticket that costs 3€. It takes you to not far from where Paris Mystique rides his bicycle.